The rCC16 Protein Protects Against LPS-Induced Cell Apoptosis and Inflammatory Responses in Human Lung Pneumocytes

Jinle Lin; Jiemei Li; Min Shu; Weigang Wu; Wenwu Zhang; Qingli Dou; Jian Wu; Xiaobin Zeng

doi:10.3389/fphar.2020.01060

The rCC16 Protein Protects Against LPS-Induced Cell Apoptosis and Inflammatory Responses in Human Lung Pneumocytes

Front Pharmacol. 2020 Jul 14:11:1060. doi: 10.3389/fphar.2020.01060. eCollection 2020.

Authors

Jinle Lin^{1

2}, Jiemei Li³, Min Shu⁴, Weigang Wu³, Wenwu Zhang¹, Qingli Dou¹, Jian Wu², Xiaobin Zeng^{3

5}

Affiliations

¹ Department of Emergency Medicine, Shenzhen Baoan First People's Hospital, Nanfang Medical University, Shenzhen, China.
² Department of Respiratory and Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Science, Guangzhou, China.
³ Center Laboratory of Longhua Branch and Department of Infectious Disease, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, China.
⁴ Emergency Department, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China.
⁵ Guangdong Provincial Key Laboratory of Regional Immunity and Diseases, Medicine School of Shenzhen University, Shenzhen, China.

Abstract

Objective: Our previous clinical study showed that low lung levels of CC16 strongly influence the occurrence and development of ARDS. The aim of the present study was to evaluate the therapeutic effect of rCC16 on LPS-induced inflammation in A549 cells and to determine its mechanism.

Methods: Cell apoptosis and inflammation was induced by LPS stimulation. The cytotoxic effect of rCC16 was evaluated using the MTT assay. Cytokine levels were determined using enzyme-linked immunosorbent assays. The molecular mechanism of rCC16 was investigated by analyzing relevant signaling pathways.

Results: The LPS treatment of A549 cells significantly decreased cell viability, increased the levels of the apoptotic proteins Bax, Bak and Cleaved Caspase-3, the secretion of inflammatory cytokines, and the expression levels of TLR4, p-NF/κB, MAPK proteins. While the levels of Bcl-2, p-AKT, p-mTOR, p-ERK1/2, NF/κB, p-AMPK, and p-p38 were significantly decreased in LPS-treated A549 cells. Our experimental results also confirmed that rCC16 inhibited LPS-induced apoptosis, promoted A549 cell proliferation by activating the PI3K/AKT/mTOR/ERK1/2 pathway, and inhibited the release of certain inflammatory factors, especially HMGB1, through dephosphorylation and inactivation of the TLR4/NF-κB/AMPK signaling pathways.

Conclusion: These results highlight the potential utility of CC16 as an important cytokine for the prevention or treatment of inflammation and show that CC16 may play an important role in the future clinical treatment of ARDS.

Keywords: Acute Respiratory Distress Syndrome; CC16; LPS; apoptosis; inflammation.